The objectives of this research are: 1), to study the central nervous events that cause locomotory behavior in lobsters; 2), to analyze the architecture of invertebrate neurons using automated computer techniques; and 3), to study the neuronal substrates of behavioral plasticity in the marine mollusk Pleurobranchaea. Forms of plasticity that are being studied are behavioral choice and associative learning (classical and avoidance conditioning of feeding behavior). As part of this study on plasticity, the neurophysiological organization of the feeding system is being analyzed.